Brake



K. E. LYMAN Aug. 30, 1932.

BRAKE Filed Aug. 20. 1927 4 Sheets-$11661l l jme/2707@ KENNETH E. LYMAN K E. LYMAN Aug. 30, 1932.

BRAKE Filed Aug. 20. 1927 4 Sheets-Sheet 2 KENNETH E LYMAN Aug. 30, 1932. K, E LYMAN 1,875,064

BRAKE Filed Aug. 20. 1927 4 Sheets-Sheet 3 j yg j@ famili/' f KENNETH E. LYM AN .ur Mfg;

Allg. 30, 1932. K, E, YMAN 1,875,064

BRAKE Filed Aug. 20, 1927 4 Sheets-Sheet 4 .ZUG/ZP KENNETH E. LYMAN Patented Aug. 30, i932 BRAKE Application Med August 20. 1927. Serial No. 214,280.

This invention relates to brakes and is illustrated as embodied in an internal expanding automobile brake. vAn important ob'ect of the invention is to provide'automatica' y operated means for adjusting the brake for wear, preferably by shifting a thrust member such as a cam roller or the like to increase the effective length ci the brake shoe or its equivalent to compensate tor the wear.

le Preferably the thrust member is adjusted by a cam, which in one form has a spiral cam slot and which in another crm is an edge cam, v and which gradually shi-.tts the thrust device forward as the brake wears to compensate for the wear by gradually increasing the eidective length of the shoe or other brake friction member. I prefer, in most embodiments of the invention, to provide a ratchet device for operatin the cam or other means, for making the descri ed adjustment.

The arrangement with a cam or other means shifting one or more rollers and their mounting embodies substantial novelty independently of the automatic operation of the adjustment.

The above and other objects and features of the invention, including various novel combinations of parts and desirable particular constructions, will be apparent from the followembodiments shown in the accompanying drawings, in which 2 Figure 1 is a vertical section through the brake just inside the head of the braise drum and showing the brake shoes in side elevation;

Figure 2 is a view on a much larger scale of the free ends of the shoes and the applying mechanism, partly broken away to illustrate the operation of the applying mechanism;

Figure 3 is a partial section through the applying mechanism on the line 3 3 of Figure 2;

Figure 4 is a view corresponding to Figure 2 but showing a different form of adjusting mechanism;

Figure 5 is a View corresponding to Figure 3 but taken on the line 5-5 of Figure 4;

Figure 6 is a view corresponding to part .cation correspondimg respectiveiy to Fig ing description of a number of illustrative of Figure 4 but showing a third form of adjusting mechanism Figure 7 is a similar view of a fourth form ot adjusting mechanism;

Figure 8 is an end elevation of the shoe oit5 f Figure 7, looking in the direction ott the arrows 8 8 in Figure 7 Figure 9 is a view corresponding to Figure 'i' but showing a fifth moditication et the invention;

Figure 10 is an end elevation ci the shoe of Figure 9 looking in the direction of the arrows 10-10 in Figure 9; and

Figures 11 and 12 are views of a modi- @5 ures 7 and 8 or 9 and 10.

The illustrated brake includes a rotatable drum 10, at the open side of which is arranged a suitable support such as a backing plate 12 and within which is arranged the triction means of the brake which in this particular design-includes three brake shoes 14 applied by means such as a double cam 16 against the resistance of return springs 18. This particular brake is substantially as more ully described in Patent No. 1,567 ,716, granted Bendix Brake Company on December 29, 1925, on an application of A. Y. Dodge.

An important feature of the present invention relates to automatically 'adjusting for wear of the brake by shifting a novel` thrust device Iwhich' preferably includes a pair of thrust rollers 20 on a-spindle 22 and engaging the applying cam 16. The cam 16 35 may be formed with a central rib as shown, which projects between the rollers 20 of each brake shoe to prevent lateral movement of thel shoe. Each of the spindles 22 is arranged in a slot 24 in the end of its shoe so that it is confined to prevent movement crosswise of the shoe but is free to have some movement lengthwise of the shoe.

In the arrangement of Figures 1, 2, and 3, each of the spindles 22 carries a fitting 30 95 arranged in a recess in the end of the shoe and which is engaged by an adjusting means such as two edge cams 32 and 33 mounted i respectively on spindles 34 and 36 journalled 1n the end of the shoe. The spindle 34 is 109 l from 5 the fitting 30 which shifts the thrust device including the.' spindle 22 and the two rollers 20.'

`The pinion 440 is formed with ratchet teeth on one end for engagement with a spring- 1 .pressed pawl 42 pivotally mounted on an arm '44 fulcrumed on a pivot -46 on the backing plate 12 and urged by a spring 48 against a sto 50.

operation, the brake-applying force the cam 16 is transmitted through the rollers 20 and the spindles 22 and through the cams 32 and 34 and their spindles to the shoes... `s the brake wears in service, the

shoes will graduall be forced further apart o by the cam when t e brake is applied, until finally the two pawls 42 snap over the next teeth ofthe ratchets on t e spindles 36, whereupon the release of the brake will operate the ratchets to turn the cams 32 and 34 g5 to shift the rollers 20 to increase the effective p lengthsof the shoes suiciently to compen- Usate'f thewear of the brake.

I'n av general way the; arrangementof Figres 4 and 5 diffats from that of Figures 1,

3 2, and 3, in that theadjusting cams and their operating means are mounted on the fitting which carries the roller s indle, and act against the shoe, insteadI of being carried by. the shoe and acting against the fitting. I In this arrangement the fitting 56 carrying roller spindle 2 is .forked to form supports for the spindles 58 and 60 of the edge cams 62and 64 engaging' an abutment or bracket 66 riveted or otherwise securedin the recess at 4 the end of the shoe. Spindle 58 carrying the cam 62 is formed with .a pinion 68 meshing with a inion 70 onthe s indle 60, the pinion 70 aving (as before? ratchet Yteeth arranged to be engaged, when the brake. is worn, by a pawl 72 urged by a spring 74 against alixed stop 76. v

In either of the above modifications the cams or their equivalentsmay be held in their adjusted positions by the friction of the parts, as illustrated, or suitable holding pawls may be provided as shown in Figure 9- if desired. The arrangement of Figure 6 is the same as that of Figures 4 and 5 in that the fitting 78 carrying the spindle 22 of the rollers 20 also carries the spindles 80 and 82 of the edge cams 84 and 86 engaging the bracket 88 on the shoe. There are also the intermeshing pinions90 and 92 on the spindles 80 and 82- 50 respectively. In this case, however, the

shifting of the cams is accomplished by a fixed stop 94 on the backing plate 12 which vengages a bell-crank lever 96 piyoted on the fitting 78, in case of excessive wear of the brake.. The rocking of the bell-crank lever 96 pulls downwardly on a pawl 98 vengaging ratchet teeth formed onone side of the pinion' 90. Return movement/of the pawl 98 is prevented by an auxiliary pawl 100- which is spring-pressed against ratchet,- teeth formed on the back of the pawl`98.

In the arrangement of` Figures 7 and 8, the spindle 22 of thei rollers 20, or an equivalent part of a thrust device carried by the shoe, not only passes throu h the slots 24 in the shoe but also through s ots 102 in cams 104 pivoted at 106 on the. brake shoe. The cam members 104 are riveted or otherwise secured to opposite sides of a ratchet 108 mounted on the spindle 106 and engaged by ay spring-pressed holding-pawl 110 to preserve the adjusted position of the spindle 22.

In this arrangement the cams 104 are operatedby a xed stop 112 on the 'backing plate 12 which is engaged by the lower. ends of the cams in case of excessive wear of thev brake, thus shifting the cams sulliciently'fto permit the pawl 110 to engage the next tooth of the ratchet 108. When the cams 104 are teeth engaged 1by-'a spring-'pressed holdingpawl 122. The adjustment in this arrangement is made by a pawl 124 mounted on a pivot 126 carried by the backing plate 12 and held byl a spring 128 against the fixed stop 130. In case of excessive wear'of the brake', the shoe is moved far-enough by the cam 16 or its equivalent so that the pawl 124 will vengage'one of the teeth of thel ratchet-and cam member 118 so that when the brake is released the return springs will cause the ratchet-and-cammember 118 to l,turn one tooth with respect to the holding-.pawl 122.-

In a general way the arrangement'of Figures 11 andA 12 is the reverse of that. of Figvures 9 and 10 in that the ratchet-and-cam member in this case moves with the thrust device 20--22, and the spiral cam.. slot engages a fixed pinA carried by the brake shoe. In the illustrated form the spindle 22 is merely a guide arranged'in the-slot24 and the.

ratchet memberl v130 is fixed directly on the spindle 22. This member is formed with a spiral cam'slot 132 embracin [a tran 'ersely extending pin A134 carriev vby the rake shoe. The holding pawl136 engaging the ratchet member 130 is in the form of a spring sufliciently flexible toifollow the movement of the ratchet member.l The operation in this case is by a pawl 138 mounted on a pin 140 carried bythe backing plate 12 and held by a springl142 against the fixed stop 144.

In case of eXcessive wear of the brake, tle pawl 138 engages the ratchet 130 and wh n the brake is released the ratchet is turn d Suiiiciently to permit the pawl 136 to eng ige the next tooth.

While several illustrative embodimens of the invention have been described in detail, it is not my intention to limit the scope )f the invention to those particular embodiments or otherwise than by the terms of the appended claims.

I claim:

l. A brake friction member having at its end at least one thrust roller having a trans verse spindle, in combination with a cam carried by the friction member and which is engaged by said spindle and which can' be adjusted to shift the roller to compensate for wear of the friction member.

2. A brake friction member having at its end a pair of thrust rollers having a transverse spindle, in combination with means engaged by a part of the spindle between the rollers and which can be adjusted to shift f the rollers.

3. A brake friction member having at its end a pair of thrust rollers having a transverse spindle, in combination with a cam engaged by a part of the spindle between the rollers and which can be adjusted to shift the rollers.

4. A brake friction member having a thrust device at one end having a transversely-extending part, in combination with an angularly-adjustable member having a spiral cam slot receiving said part. l

5. A brake friction member having a thrust device at one end having a transversely-extending part, in combination with an singularly-adjustable member having a spiral cam slot receiving said part, said member being formed with ratchet teeth, together with a separately-mounted pawl engageable with said teeth.

6. A brake friction member having a thrust device at one end having a transversely-extending part, in combination .with an angularly-adjustable member having a spiral cam engaging said part.

7. A brake element having a thrust roller at one end, and a cam for adjusting the roller bodily lengthwise of the element.

8. A brake element comprising two stampings spread apart at one end of said element, and having adjustable thrust means mounted at least in part between the spread-apart portions of the stampings.

-between the spread-apart portions of the stampings for shifting the roller means bodily to adiust for wear.

10. A bralre element comprising stampings KENNETH E. LYMAN. 

